<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="style.css">
    <title>CSS Flex布局练习</title>
</head>
<body>
    <div class="panel">
        <input type="text" placeholder="输入框">
        <input type="button" value="输入">
    </div>
    <div class="panel">123</div>
    <div class="panel">123</div>
    <div class="panel">123</div>
    <div class="panel">123</div>    
</body>
</html>